The invention is in the field of bicycle wheel hubs and relates particularly to hubs used in bicycles designed for off-road use.
Before the advent of off-road-designed bicycles, bicycles traditionally, or at least in the last few years, have utilized front and rear wheel hub assemblies which are substantially different from one another and by no means interchangeable. In addition to the rear wheel hub having an integral freewheel mechanism mounting sleeve, the rear hub axle, and thus the axle housing and bearings, were ordinarily larger than the comparable parts of the front wheel hub.
However, the recent trend in off-road bicycle design is to provide both axles and the accompanying parts in identical sizes. Because of the nature of off-road bikes it is also desirable to be able to easily change the size of the rear wheel sprocket because off-road bikes ordinarily do not have the sophisticated gear mechanisms of the ten-speed bicycles popular for street use. Despite this, it has been traditional to require the replacement of the entire freewheel mechanism, or at least a major portion including the sprocket itself and the outer ball race due to the contruction of the rear wheel hub.
In addition, because the mounting structure of the rear hub on which the free wheel mechanism is threaded is integral with the hub, front and rear hubs are both designed independently and separately even though axle size is now uniform front and back.